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CSA Z5300-2019 pdf free download
CSA Z5300-2019 pdf free download.Cellulose filaments ( CF ) – Preparing handsheets for physical tests.
Handsheet formation shall be as follows:
a) Use 400-mesh screens to ensure high CF retention.
Note: Standard hondsheet machine grid plates ore equipped with 150-mesh screens (see Figure !4 b)j.
b) With the handsheet machine deckle open, close the drain valve and turn on the water.
c) Gently rub the surface of the 400-mesh screen with your fingertips to dislodge any adhering fibres. Do not use brushes or other tools, which can damage or loosen the screen. Ensure hands are clean to avoid contaminating the screen; gloves are not recommended as they can make it difficult to detect fibres.
d) Repeat b) and c) twice more, or until the screen is clean.
e) Stop adding water and then close the deckle. A thin layer of water should be at the surface of the screen at all times before adding the diluted CF suspension. This ensures that water Is present below the screen to prevent filtration of CF through the screen before the drain valve is opened. It also ensures that drainage begins immediately upon opening the valve.
f) Calculate the mass of 0.3 wt% CF suspension needed to obtain 0.4 g o.d. CF, or a 20 g/m2 CF handsheet.
g) Using a plastic ladle, stir the suspension to ensure that the CF Is uniformly dispersed and then pour into a 1 1 plastic beaker.
h) Dilute the CF to a final total volume of 800 ml to obtain a final consistency of around 0.05 wt%.
I) Gently stir with a plastic spatula then carefully transfer the 800 mL suspension into the handsheet machine. Do not pour the CF suspension down the side of the deckle walls, as some fibres can remain on the walls and affect the haridsheet basis weight.
j) Gently stir the suspension with a plastic spatula in the handsheet machine. Avoid any rotational movement, which can cause a heavy area in the centre of the sheet and “segregation” of lighter fines and heavier fibres; it is preferable to make a W shape movement 4 times. Be careful not to scratch the screen.
k) After stirring, wait 10 s for the suspension to stabilize, and then slowly open the drain valve. Note: Measuring the drainage time with a stopwatch provides a rapid assessment of the CF quality; longer drainage times indicate better quality CF. Drainage times con range from seconds to a few minutes, with good quality CF typically taking at least 30 s.
I) Once the CF handsheet is formed and immediately after the water is no longer visible (i.e., the haridsheet does not look wet or shiny), close the drain valve and open the deckle.
Note: This procedure con also be used to produce CF handsheets of basis weight 5 to 40 g/m. However, at basis weights below 20 g/m2,. it is difficult to obtain repeatable handsheet properties.
Couching removes some of the water and ensures that the damp CF handsheet sticks to the filter paper for structural stability during pressing, and manipulation. Use caution when handling the heavy 13 kg couch roll.CSA Z5300-2019 pdf free download.
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